Archive for October, 2008

For the best sense of an area’s geology you need to see it at as many scales as possible. I study this city from eye level and ground level, also by staring at maps. I climb its hills and go beyond its borders to survey it from a distance. If I had a light plane, I’d cruise all over from a thousand feet up. (In its absence, Google Earth and Google Maps are quite useful.)

Another of my practices is to climb parking structures. The views are always good, but nobody else does this—these buildings aren’t reaching their full potential! This shot is from the top of the Kaiser Hospital’s parking structure during a spectacular sunset in the winter of 2003. That’s Piedmont Avenue below. Round Top pokes above the large apartment building at center right. The knob at farthest left is now occupied by a very large house, looking down on the rest of the Hiller Highlands. Imagine having a public park bench up there.

I don’t know why I call this knocker nine, since the last set of Mountain View Cemetery knockers I posted should be number 8 through 11. But I can be inconsistent in my domain, and besides I think it just looks like knocker nine. This mini-outcrop in the Franciscan mélange is on Piedmont town land, on the hillside above the skateboard park south of the cemetery. The rocks are no respecters of property lines or jurisdictions.

I’m headed out of town for a few days, so talk amongst yourselves if you like. I’ll be in Las Vegas and enroute by car, taking a loop down into deepest Imperial County.

October 21 is the date of the 1868 Hayward earthquake. It was on the order of a magnitude 7 and caused widespread destruction plus a couple dozen deaths. Over the last 2000 years, the Hayward fault has had large earthquakes at an average of every 140 years, and this year marks 140 years since 1868. There will be a public gathering on the 21st, at the Mission San Jose, at 7:55 a.m., the time of the quake. (At least it wasn’t at 5:13 a.m. like the 1906 quake.)

Unfortunately the officials are making the same mistake the San Franciscans do, which is to ignore daylight saving time and time zones generally. In 1868, cities determined their time locally from astronomical noon (or used the time of a larger regional city), so the contemporary time must be adjusted for us to experience the setting of that earthquake at the correct time of day. I don’t happen to know if Hayward used San Francisco time in that year, or if both cities used Sacramento time. In 1906, California was on Pacific standard time year-round, and 5:13 a.m. on April 18 was nearly sunrise, but nowadays they observe the moment, in a ceremony at Lotta’s Fountain, in the dark of night an hour earlier.

Oh, the photo? It’s the little valley across the freeway north of the zoo, where Arroyo Viejo makes a right-hand jog as it crosses the Hayward fault. We’re looking across the fault from Calandria Avenue in early 2005. The hill on the far side is a shutter ridge, cruising north at a long-term rate of about half an inch a year, which it does in meter-sized jumps every couple centuries. (It moved in 1868.) The hill has a large covered reservoir on top of it, to the left of this photo; you could easily imagine it rupturing in a large quake. That doesn’t mean it will rupture, because it’s well engineered, but it’s easy to imagine it failing. In the middle is Holy Redeemer College.

October 17 always has an ominous ring to it, because of the Loma Prieta earthquake of 1989 (or “the big-enough one“). In Oakland, we were distant from the epicenter, which is just visible on a clear day in the mountains beyond San Jose. But it was on this spot where the double-decker Cypress Structure, part of the Nimitz Freeway, felt its soft ground give way and collapsed, the deadliest single place in the whole disaster. I remember riding BART into the Oakland West station (remember when they called it that?) and sensing the whole carful of riders hold its breath as the wreckage came into view.

It was an ugly, traumatizing mess for years and years. In 2005, when I took this photo from the BART station on January 28, the Mandela Gateway complex at the base of Mandela Parkway was new, landscaping along the road was under way, and the area seemed nearly finished. But if you know where to look as you ride west from the downtown stations, you can still see the curved trace of the old freeway in the lines of the buildings and lots. Earthquakes are forever.